I had already turned ON the USB Debugging on my phone and installed the drivers before I tried to do this.
I tried to root my Samsung Galaxy Prevail with SuperOneClick and this happened:
Killing ADB Server...
* server not running *
Starting ADB Server...
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
Waiting for device...
Checking if rooted...
Installing BusyBox (temporary)... - Step #1
683 KB/s (1062992 bytes in 1.519s)
Installing BusyBox (temporary)... - Step #2
Rooting device... - Step #1
1093 KB/s (585731 bytes in 0.523s)
Rooting device... - Step #2
Rooting device... - Step #3
Rooting device... - Step #4
property service neutered.
killing adbd. (should restart in a second or two)
Rooting device... - Step #5
Remounting /system with read-write access...
mount: Operation not permitted